nix-dots/modules/services/forgejo/default.nix

{
  config,
  lib,
  pkgs,
  ...
}:
with lib; let
  cfg = config.my.services.forgejo;
  inherit (config.my.server) domain proxyIP firewallInterface;
  forgejoDomain = "git.${domain}";
  forgejoUrl = "https://${forgejoDomain}";

  # for nix actions runner
  storeDeps = pkgs.runCommand "store-deps" {} ''
    mkdir -p $out/bin
    for dir in ${
      toString [
        pkgs.coreutils
        pkgs.findutils
        pkgs.gnugrep
        pkgs.gawk
        pkgs.git
        pkgs.nix
        pkgs.bash
        pkgs.jq
        pkgs.nodejs
        pkgs.devenv
      ]
    }; do
      for bin in "$dir"/bin/*; do
        ln -s "$bin" "$out/bin/$(basename "$bin")"
      done
    done

    # Add SSL CA certs
    mkdir -p $out/etc/ssl/certs
    cp -a "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt" $out/etc/ssl/certs/ca-bundle.crt
  '';
in {
  options.my.services.forgejo = {
    enable = mkEnableOption "Forgejo";
    proxy = mkEnableOption "Forgejo reverse proxy entry";
    actions = mkOption {
      type = types.submodule (_: {
        options.enable = mkEnableOption "Forgejo Actions";
      });
    };
    subdomain = mkOption {
      type = types.str;
      default = "git";
      example = "git";
      description = "Subdomain to use for the service.";
    };
    port = mkOption {
      type = types.port;
      default = 3000;
      example = 8080;
      description = "HTTP port for the Forgejo service.";
    };
  };

  config = mkMerge [
    (mkIf cfg.enable {
      age.secrets.forgejoSendgridKey = {
        file = ../../../secrets/sendgrid-key.age;
        owner = "forgejo";
        group = "forgejo";
      };
      services.forgejo = {
        enable = true;
        package = pkgs.unstable.forgejo;
        settings.server = {
          DOMAIN = forgejoDomain;
          ROOT_URL = forgejoUrl;
          DISABLE_SSH = true;
          HTTP_PORT = cfg.port;
        };
        settings.session = {
          COOKIE_SECURE = true;
        };
        settings.service = {
          DISABLE_REGISTRATION = true;
        };
        settings.openid = {
          ENABLE_OPENID_SIGNIN = true;
          ENABLE_OPENID_SIGNUP = true;
        };
        settings.oauth2_client = {
          ENABLE_AUTO_REGISTRATION = true;
        };
        settings.mailer = {
          ENABLED = true;
          FROM = "forgejo@michaelt.xyz";
          PROTOCOL = "starttls";
          SMTP_ADDR = "smtp.sendgrid.net";
          SMTP_PORT = 587;
          USER = "apikey";
        };
        mailerPasswordFile = config.age.secrets.forgejoSendgridKey.path;
      };

      networking.firewall.interfaces."${firewallInterface}".allowedTCPPorts = [cfg.port];
    })
    (mkIf cfg.actions.enable {
      # build image // taken from https://git.clan.lol/clan/clan-infra/src/branch/main/modules/web01/gitea/actions-runner.nix
      # everything here has no dependencies on the store
      systemd.services.forgejo-runner-nix-image = {
        wantedBy = ["multi-user.target"];
        after = ["podman.service"];
        requires = ["podman.service"];
        path = [
          config.virtualisation.podman.package
          pkgs.gnutar
          pkgs.shadow
          pkgs.getent
        ];
        # we also include etc here because the cleanup job also wants the nixuser to be present
        script = ''
          set -eux -o pipefail
          mkdir -p etc/nix

          # Create an unpriveleged user that we can use also without the run-as-user.sh script
          touch etc/passwd etc/group
          groupid=$(cut -d: -f3 < <(getent group nixuser))
          userid=$(cut -d: -f3 < <(getent passwd nixuser))
          groupadd --prefix $(pwd) --gid "$groupid" nixuser
          emptypassword='$6$1ero.LwbisiU.h3D$GGmnmECbPotJoPQ5eoSTD6tTjKnSWZcjHoVTkxFLZP17W9hRi/XkmCiAMOfWruUwy8gMjINrBMNODc7cYEo4K.'
          useradd --prefix $(pwd) -p "$emptypassword" -m -d /tmp -u "$userid" -g "$groupid" -G nixuser nixuser

          cat <<NIX_CONFIG > etc/nix/nix.conf
          accept-flake-config = true
          experimental-features = nix-command flakes
          NIX_CONFIG

          cat <<NSSWITCH > etc/nsswitch.conf
          passwd:    files mymachines systemd
          group:     files mymachines systemd
          shadow:    files

          hosts:     files mymachines dns myhostname
          networks:  files

          ethers:    files
          services:  files
          protocols: files
          rpc:       files
          NSSWITCH

          # list the content as it will be imported into the container
          tar -cv . | tar -tvf -
          tar -cv . | podman import - forgejo-runner-nix
        '';
        serviceConfig = {
          RuntimeDirectory = "forgejo-runner-nix-image";
          WorkingDirectory = "/run/forgejo-runner-nix-image";
          Type = "oneshot";
          RemainAfterExit = true;
        };
      };

      users.users.nixuser = {
        group = "nixuser";
        description = "Used for running nix ci jobs";
        home = "/var/empty";
        isSystemUser = true;
      };
      users.groups.nixuser = {};

      # configure the actions runner itself
      age.secrets.forgejoActions.file = ../../../secrets/forgejo-actions.age;
      services.gitea-actions-runner = mkIf cfg.actions.enable {
        package = pkgs.unstable.forgejo-runner;
        instances.venus = {
          enable = true;
          name = "venus-nix-runner";
          url = forgejoUrl;
          settings = {
            # options = "-v /var/run/podman/podman.sock:/var/run/podman/podman.sock";
            runner = {
              capacity = 5;
              timeout = "45m";
            };
            container = {
              options = "-e NIX_BUILD_SHELL=/bin/bash -e PAGER=cat -e PATH=/bin -e SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt --device /dev/kvm -v /nix:/nix -v ${storeDeps}/bin:/bin -v ${storeDeps}/etc/ssl:/etc/ssl --user nixuser --device=/dev/kvm";
              # privileged = true;
              valid_volumes = [
                "/nix"
                "${storeDeps}/bin"
                "${storeDeps}/etc/ssl"
              ];
              # force_pull = false;
              network = "bridge";
            };
          };
          labels = [
            "nix:docker://forgejo-runner-nix"
          ];
          tokenFile = config.age.secrets.forgejoActions.path;
        };
      };
    })
    (mkIf cfg.proxy {
      services.caddy.virtualHosts."${forgejoDomain}".extraConfig = ''
        handle_errors {
          respond "This server is currently unavailable." 502
        }

        redir /user/login /user/oauth2/Keycloak?{query}

        reverse_proxy http://${proxyIP}:${toString cfg.port}
      '';

      webapps.dashboardCategories = [
        {
          name = "Git";
          tag = "git";
        }
      ];

      webapps.apps.forgejo.dashboard = {
        name = "Forgejo";
        category = "git";
        icon = "git-alt";
        url = forgejoUrl;
        description = "Beyond coding. We forge.";
      };
    })
  ];
}